POWER BI INTERVIEW QUESTIONS WITH ANSWER

1. What is Power BI and how is it different from other BI tools?

Power BI is a business analytics tool by Microsoft used for analyzing data and sharing insights. It stands out due to its user-friendly interface, integration with other Microsoft products, and robust visualization capabilities.

2. Explain the difference between Power BI Desktop, Power BI Service, and Power BI Mobile?

Power BI Desktop is a desktop application for creating reports and visualizations. Power BI Service is a cloud-based service for publishing, sharing, and collaborating on reports. Power BI Mobile is a set of mobile apps for accessing and interacting with Power BI content on mobile devices.

3. What is DAX and how is it used in Power BI?

DAX (Data Analysis Expressions) is a formula language used in Power BI to create calculated columns, measures, and calculated tables. It allows users to perform complex calculations and aggregations on data.

4. How does Power Query help in data preparation?

Power Query is a data connection and transformation tool used to import, transform, and clean data from various sources before loading it into Power BI. It helps in tasks such as data filtering, sorting, merging, and pivoting to prepare data for analysis.

5. What are calculated columns in Power BI and when would you use them?

Calculated columns are columns created in Power BI by applying a DAX formula to an existing table. They are computed during data refresh and stored in the data model. Calculated columns are useful for creating new static columns based on existing data.

6. What are measures in Power BI and when would you use them?

Measures are dynamic calculations performed at query time based on the context of the visualization or filter selection. They are not stored in the data model and are recalculated on the fly. Measures are used for aggregations, calculations based on filtered data, or complex calculations involving multiple tables.

7. Explain the concept of row-level security in Power BI?

Row-level security (RLS) in Power BI restricts data access based on user roles and permissions. It allows administrators to define rules that determine which rows of data a user can access based on their role.

8. How does Power BI handle large datasets and ensure performance?

Power BI offers features like data compression, partitioning, and incremental refresh to handle large datasets efficiently. It also supports DirectQuery mode for real-time access to large datasets without importing them into the data model.

9. What are the different types of joins available in Power BI?s available in Power BI?

Power BI supports inner join, left join, right join, and full outer join between tables using the Merge Queries or the Relationship feature in the Query Editor.

10. What is the role of the Power BI Gateway?

The Power BI Gateway acts as a bridge between on-premises data sources and the Power BI Service in the cloud. It allows Power BI Service to access and refresh data from on-premises data sources securely.

11. How can you schedule data refresh in Power BI Service?

In Power BI Service, you can schedule data refresh for datasets by configuring a refresh schedule in the dataset settings. This ensures that the data stays up-to-date with the underlying data sources.

12. What is Power BI Paginated Report Builder and how does it differ from Power BI Desktop?

Power BI Paginated Report Builder is a standalone tool used to create pixel-perfect, paginated reports with precise control over layout and formatting. It differs from Power BI Desktop, which is more focused on interactive, analytical reports.

13. Explain the concept of composite models in Power BI?

Composite models in Power BI allow users to combine data from both imported datasets and DirectQuery sources in the same data model. This enables users to create reports that span across different data sources seamlessly.

14. How does Power BI integrate with Azure services?

Power BI integrates with various Azure services such as Azure SQL Database, Azure Data Lake Storage, Azure Synapse Analytics, and Azure Analysis Services for data storage, processing, and analysis.

15. What is the role of Power BI Embedded and when would you use it?

Power BI Embedded is a platform-as-a-service (PaaS) offering that allows developers to embed Power BI reports and dashboards into custom applications. It is used when organizations want to integrate analytics directly into their applications for end-user consumption.

16. Explain the difference between calculated columns and measures in Power BI?

Calculated columns are computed during data refresh and stored in the data model, while measures are dynamic calculations performed at query time based on the context of the visualization or filter selection.

17. How can you optimize Power BI reports for better performance?

Power BI reports can be optimized for better performance by simplifying data models, minimizing the number of visuals per page, using efficient DAX formulas, and leveraging features like aggregations and query folding.

18. What is the role of Power BI Premium and when would you use it?

Power BI Premium is a capacity-based licensing model that offers dedicated resources for deploying large-scale BI solutions. It is used when organizations require advanced features like increased dataset sizes, paginated reports, and AI capabilities.

19. How does Power BI support natural language queries and visualizations?

Power BI supports natural language queries and visualizations through its Q&A (Question and Answer) feature, which allows users to ask questions in plain language and get visualizations as answers.

20. What are the different types of filters available in Power BI?

Power BI supports various types of filters including visual-level filters, page-level filters, report-level filters, and slicers that allow users to interactively filter data in reports.

21. How can you create a hierarchy in Power BI?

To create a hierarchy in Power BI, you can select multiple columns in a table and create a hierarchy by right-clicking and choosing the "Create Hierarchy" option. Hierarchies help in organizing and drilling down data in reports.

22. Explain the concept of bookmarks in Power BI and how they are used.

Bookmarks in Power BI allow users to capture the current state of a report, including filters, slicers, and visual selections, and save it for later reference. They are useful for creating guided navigation experiences within reports.

23. What are the different types of data sources supported by Power BI?

Power BI supports a wide range of data sources including Excel files, SQL Server databases, Azure services, SharePoint lists, Salesforce, Google Analytics, and many others.

24. How can you create a calculated table in Power BI?

To create a calculated table in Power BI, you can use the "New Table" option in the Power Query Editor or create a calculated table directly in the data model using DAX formulas.